The Trapped Key Interlock line from KIRK interlocking products provides safe access to switchgear within HV substations. Trapped key access interlocks and key exchange units restrict physical entry and prevent dangerous operating conditions, ensuring that personnel operate equipment according to the correct sequence of operation.
Trapped key interlocking utilizes locks and keys for sequential control of equipment and machinery. Trapped key interlocks are widely used to ensure safe access to potentially live or dangerous plant or equipment in an industrial setting. A safe sequence of operations is enabled through transfer of keys that are either trapped or released in a predetermined order.
A trapped key interlock prevent injury to personnel, protects equipment from damage, and assures continuity of electrical supply by initially restricting any unauthorized access. This is particularly important for HV substations located in remote, unmanned sites. Secondly, they ensure that all authorized access is done in a safe manner, requiring that part of a system is isolated and correctly earthed before maintenance can be carried out on that section.
A well-designed interlocking scheme also ensures that the system is operated correctly. This can prevent a number of dangerous scenarios such as: switching two incoming feeds onto a common bus bar, the paralleling of two energy sources, or disconnecting breakers under load. This greatly reduces the risk of fire or arc flash, further protecting equipment from damage, preventing injury, and avoiding supply interruption.
For HV substation applications, Kirk recommends its HD Series interlocks. The lock housing, cylinder, and inner workings are manufactured entirely of 316 stainless steel. A robust dowel pin key design resists breakage and prevents duplication. A gasketed flip cover protects the keyways from debris. The HD Series range includes mechanical and electromechanical bolt, access, transfer, and valve interlocks, along with a full range of accessories to form a comprehensive switchgear interlocking scheme for HV substations.